Well drilling apparatus



Feb. 2, 1965 J. PAROLA WELL. DRILLING APPARATUS Filed Jan. 29, 1962 mA mm R Wm M a United States Patent 3,168,287 WELL DRILLING APPARATUS Jean Parola, Rueil-Malmaison, France, assignor to lnstitut Francais du Petrole, ties Carhurants et Lubrifiants,

Rueil-Malmaison, France Filed Jan. 29, 1962, Ser. No. 169,391 Claims priority, application France Jan. 30, 1961 7 Claims. (Cl. 254175.7)

The present invention relates to a well drilling apparatus utilizing flexible tubing, more particularly, to an arrangement for avoiding stresses on the flexible tubing while on the winding drum.

In certain drilling operations the drill bit is actuated by means of a bottom boring machine such as an electric motor or a hydraulic turbine, which is suspended on the end of a flexible tubing. The drilling liquid passes throughthe tubing which may be provided with electric conductors to connect the bottom boring machine with a source of electric current.

In such a case the surface apparatus used for operating the drill string, i.e. for winding and unwinding the flexible tubing or hose supporting the bottom boring machine and the drilling bit, generally comprises a motor winch of a conventional type.

The drum of this winch is actuated by a motor of suitable power through a transmission system which simultaneously provides.

Either for the traction and the winding of the flexible hose during the withdrawal of the drill string,

Or for the unwinding of the flexible hose and control thereof during the lowering of the drill string into the well.

Such a motor winch may be used with a lifting device of the conventional type such as a derrick or a tower provided with upper and lower pulleys (e.g. crown block and travelling block) over which is passed the flexible hose. Such pulleys have a diameter which cannot be arbitrarily selected but must relate to the structural characteristics of the derrick or the tower.

However, such arrangements suffer from the disadvantages of subjecting the flexible hose to simultaneous tension, bending-torsional and compression stresses which are detrimental on one hand to a normal circulation of both the drilling liquid and electric current and, on the other hand, to the mechanical strength of the flexible tube over a long period of time.

It is therefore an object of the present invention to avoid these disadvantages by using an apparatus for handling the hose wherein the traction part is separated from the winding part.

It is another object of this invention to provide means for handling the hose so as to substantially avoid subjecting the hose to bending-torsion and crushing on the winding drum.

It is still another object of this invention to provide a simplified lifting device of reduced bulk for handling, and particularly for lowering and raising, flexible tubings into and out of a well.

It is a further object of this invention to provide a lifting device adapted to maintain the flexible tubing in substantially rigid alignment during the drilling operation and to raise and lower the rigid terminal part of the drill string, consisting essentially of the bot-tom motor, a few drill collars and the drilling bit.

These and other objects and advantages are achieved according to this invention by the use of a surface a-pparatus essentially comprising a capstan over which is passed the flexible tubing and a lifting device therefor consisting of two substantially vertical mats between which said capstan is slidably mounted.

3,1ii8287 Patented Feb. 2, 1965 Still other objects and advantages of this invention will be apparent upon consideration of the accompanying specification and the following drawings, which constitute a part of said specification and wherein FIGURE 1 is a somewhat schematic perspective view of the general assembly of the surface apparatus according to this invention.

FIGURE 2 is a cross-section of half of a capstan according to this invention, having three winding turns of hose on it; and

FIGURE 3 is a cross-section similar to FIGURE 2 and shows a modification of the capstan according to this invention.

Referring first to FIGURE 1, it will be apparent from the general assembly of the surface apparatus shown therein that the longitudinal traction stresses to which the flexible tube is subjected which traction stresses result from the weights of the drill bit, the bottom boring machine, the tubing itself and a few drill collars if needed, are entirely supported, according to this invention, by the capstan. The number of windings of the tube on the capstan will be so selected as to distribute said stresses over a sulficient area of the tube, which area may be considerably increased by providing the capstan with grooves fitting as close as possible the shape of the tube.

Moreover, the grooves of the capstan will be preferably made of an elastic material 21 having a coeflicient of fritcion with the tube which is judiciously selected so as to distribute the stresses on the whole wound length of the tube and have them better absorbed by a given friction area.

For this purpose the capstan body is provided with an elastic member secured on it. Said elastic member may be advantageously arranged with helical grooves corresponding in shape to the tube (FIGURE 2) or it may be capable, by pressure effect to adapt itself to the tube shape (FIGURE 3). According to each case such an elastic member may consist, for instance, of an elastic bed which may be provided with springs or a pneumatic, hydraulic or oil cushion.

In these latter cases, where the pressure of a fluid is employed to force the cushion against the external wall of the tube, it is convenient to arrange the recesses destined for the fluid inside the cushion, in the form of communicating cells (see FIGURE 3) so as to maintain the external surface of the cushion sufliciently integral with the internal surface therof which is secured on the capstan body. The elastic member is so constructed that each portion of said member destined to support one given winding or turn of the flexible tube may have an elasticity different from that of other portions supporting other turns. It is preferable to adjust the elasticity of the system separately for each portion of the same, bearing a different winding turn, so as to obtain better distribution of the stresses over all of the windings or turns.

For this purpose, each of said portions of the elastic member may either be provided with springs differently calibrated or consists of a number of separate tight compartments of cushion provided with internal cells subjected to different fluid pressures. This number would correspond to the number of windings of the tube on the capstan body.

The elastic member secured on the capstan body may be made of various materials including, for instance, natural rubber and synthetic elastomers such as neoprene.

Among these various materials will be preferably selected those exhibiting a suflicient mechanical strength and having a convenient friction coeificient on the material of the tube.

The operation of the surface apparatus according to this invention will be described more in detail with efere'nce to the accompanying drawings.

A capstan 1 is driven, for instance, by means of an electric motor 2 coupled therewith through a gear, a clutch or a dog-clutch, the direction of rotation of which may be reversed at will. The lowering and withdrawing of the tubing are thus carried out by means of a single control of the motor driving the capstan.

At the output of the capstan the flexible tube is directly wound on a reel 3, driven, for instance, by a motor 4 operated at constant torque. The running speed of the motor is automatically adjusted to that of the capstan so that the tube is not subjected to any traction stresses except the small one-corresponding to, the weight of the tube length 5 between the capstan and the reel.

The reel 3, which is rotatably mounted on a support 6,.and the corresponding driving means 4 may accordingly be considerably simplified and reduced in volume, which olfers the further advantage of facilitating the coupling of several tubing lengths stored'on various reels of convenient size and weight. The various tubing lengths are provided with convenient coupling sleeves and the coupling or uncoupling of two adjacent tubing lengths is carried out when the coupling sleeves have a position intermediate between the reel and the capstan. .The motion of the capstan is arrested and the movement of the tubing blocked by means of a detachable buffer-stop 7 constituted by joining lateral elements 8 and 9 which are pivotally mounted on the platform 14. 'The buffer-stop is placed behind the sleeves so as to neutralize the traction stresses, as shown in FIGURE 1.

In order to pass the coupling sleeves of 'the'tube onto the cylindrical capstan body, it is convenient to place on said cylindrical body an elastic member of appropriate shape to support the sleeves and the adjacent portions of the tubing so as to reduce the bending stress to which the latter is subjected. i V

. On FIG. 3 the elastic mattresses comprise three cellular chambers 16, 17 and 18, corresponding to three turnsof:

machine, it necessarily comprisesa rigid part corresponding to the boring machine and the few drill collars surmounting the same, which are used for applying to the drill bit' a sufiicient weight to assure a vertical positioning of the bore hole. For raising and lowering this rigid part of the drill-string a lifting device'of an appropriate height is required. It is an object of this invention to provide such a lifting device for cooperation with the capstan so as to avoid any detrimental effect on the mechanical strength of the tube and its components.

The lifting device according to this invention, as illustrated by way of example, in FIGURE 1, essentially comprises two vertical masts 10 and 11 having slidably mounted therebetween an elevating member '13 consisting .of a support on which the capstan 1'is rotatably mounted. The elevating member is actuated by a cable 15 operatively connected to a winch 12. V

In the upper position of the elevating member, the

capstan is freely rotatable about its axis. In the lower position, shown in FIGURE 1, wherein the elevating member 13 rests on the platform 14 (which supports the two masts and the capstan therebetween as well as the winch and the motor), the capstan is coupled with the motor, through a reduction gear system, preferably'of the Worm reduction gear type. The lowering and raising into and out of the well of this rigid part of the drillstring (drill bit, boring machine and eventually drill collars) is effected by actuation of the elevating member either when starting the drilling operation or toward the end of the Withdrawal of the drill-string. Since at such moments the'traction stresses on the tube are relatively low, the capstan, may be allowed tov freely revolve without inconvenience. The motor 4 at constant torque which operates the reels 3, has sufiicient power for lowering or raising the rigid part of the drillstring. The latter may be maintained vertical; i.e. parallel to the two masts, by means of a' number of guides (not shown in the accompanying drawings) detachably mounted on said masts and preferably regularly spaced from one another over the entire height of the masts. However, such guides are not actually necessaryif, when starting the drilling operation, the tube, to which is suspended the rigid part of the drill-string, is kept subjected to traction stresses.

The drilling operation is conducted by progressively lowering the elevating member 13 in proportionto the depth drilled, the guides, if any, being progressively with-. drawn as the drilling proceeds. As soon as the elevating member attains its lower position (shown in FIGURE 1) which corresponds to a drilled depth equal to the length of the rigid part of the drill-string, the motor 2 is coupled to the capstan -1 by means of which the drill-string is unwound.

It must be observed that any convenient control system may be used to operatively connect the bottom boring machine driving the drilling bit to the surface motor driving the capstan so as to adjust the unwinding speed of the flexible tubing to the boring speed, whereby an automatically controlled drilling is achieved.

By way of a specific example of this invention, the main characteristics of the surface apparatus according to this invention are given below for illustrative purposes only.

I (I) CAPSTAN Diameter 2 meters. Number of winding turns 4.

Driving means of the capstan A variable speed electric motor 2 provided with a wire-wound rotor, trademark CEM, power: 40 H.P., fed with current at 220 or 380 volts, provided with a device for reversing the revolving direction.

A worm reducing gear.

' A transmission of movement to the capstan and connecting means with the latter comprising a dog-clutch.

Structure of the capstan (II) REEL Mounted on a ski-platform, the reel has the following characteristics: Meters Diameter of the side-jaws 2.600 Diameter of the drum 1.600 Width of the drum 1.170.

7 Capacity of the reel expressed in meters of tube of a mm. diameter 530 The' driving engine 4 consists of an assembly of a motor operated at constant torque and reducing gears, trademark CEM, torque: 4.5 rn./kg. The entire system is provided with a hand brake and a locking bar.

Weight without the flexible tubing: 3 metric tons.

(III) LIFTING DEVICE Mounted on a platform 9.7 m. long and 2.0 m. wide, it

comprises:

Two tube masts having A diameter of 178 mm.

A total height of 11.36 m. supporting a maximum force of 47.8 metric tons and provided with pivot connection means at 2.50 meters from the lower part thereof, for lowering the masts to a horizontal position or raising back the same to a vertical position, by means of two lifting jacks.

A hydraulic lifting device for the masts consisting of two hydraulic jacks, trademark Etna An operating winch 12 provided with two drums, trademark Sitra Driven by means of an electric motor (trademark Novacem) power: H.P., speed: 1.500 r.p.m. fed with current at 220 or 380 volts and a clutch (trademark Turco) 2 speed gears for respectively raising speeds of 3 and 6 meters per minute with respective traction forces of 10.5 and 5.3 metric tons 1 speed gear for a lowering speed of 3 meters per minute.

One of the drums controls the operation of the elevating member and the other a two-rope block for auxiliary movement control.

Total weight: 4 metric tons.

It will be understood that, while there have been given herein certain specific examples of the practice of this invention, it is not intended thereby to have this invention limited to or circumscribed by the specific details of materials, size or conditions herein specified for illustrative purposes, in view of the fact that the invention may be modified according to individual preference or conditions without necessarily departing from the spirit of this disclosure and the scope of the appended claims.

What is claimed as this invention is:

1. In a surface apparatus for handling a drill-string having a rigid part comprising a well boring machine, said rigid part being suspended on a flexible tubing, the combination of reel means for the storage of the flexible tubing by winding of the same thereon, a lifting device comprising two vertical masts, a capstan comprising a body and so mounted between said vertical masts as to be slidable therealong over a length thereof at least equal to the height of said rigid part of the drill-string, a motor operatively connected to said capstan in the lowermost position thereof and disconnected in any other position of the capstan and means on said capstan body for frictionally holding the tubing so as to substantially neutralize the traction, bending-torsional and crushing stresses to which the tube is subjected on that part of the tube which is Wound on said reel means.

2. A surface apparatus according to claim 1 wherein said holding means consist of an elastic member secured on the body of the capstan and provided with inner recesses connected to a fluid under pressure having the effect of forcing the external wall of said member against the external surface of that part of the tubing in contact with it, whereby this external wall is caused to fit the tubing shape, which results in an increased friction coeflicient between said member and the tubing.

3. A surface apparatus according to claim 2 wherein said elastic member comprises a plurality of separate non-communicating recesses, sealed from one another and subjected to different fluid pressures.

4. A surface apparatus according to claim 3 wherein said separate recesses correspond in number and in location to the different winding turns of the tubing on the capstan body.

5. A surface apparatus according to claim 1 whereinsaid capstan is driven by means of an assembly of a motor and reducing gears provided with a reversing device.

6. A surface apparatus according to claim 1 wherein said reel means are driven by means of a motor operated at constant torque, the revolving speed of which is automatically adjusted to that of the capstan.

7. A surface apparatus according to claim 1 wherein said means for slidably mounting said capstan between said two vertical masts comprises a slidable elevating member having said capstan rotatably mounted thereon and actuated by winch means.

References Cited in the file of this patent UNITED STATES PATENTS 339,459 Wells Mar. 12, 1889 1,396,721 Atwood Nov. 15, 1921 1,661,275 Stensland Mar. 6, 1928 2,869,826 Thornburg Jan. 20, 1959 2,991,977 Petersen et a1. July 11, 1961 FOREIGN PATENTS 255,302 Great Britain July 22, 1926 

1. IN A SURFACE APPARATUS FOR HANDLING A DRILL-STRING HAVING A RIGID PART COMPRISING A WELL BORING MACHINE, SAID RIGID PART BEING SUSPENDED ON A FLEXIBLE TUBING, THE COMBINATION OF REEL MEANS FOR THE STORAGE OF THE FLEXIBLE TUBING BY WINDING OF THE SAME THEREON, A LIFTING DEVICE COMPRISING TWO VERTICAL MASTS, A CAPSTAN COMPRISING A BODY AND SO MOUNTED BETWEEN SAID VERTICAL MAST AS TO BE SLIDABLE THEREALONG OVER A LENGTH THEREOF AT LEAST EQUAL TO THE HEIGHT OF SAID RIGID PART OF A DRILL-STRING, A MOTOR OPERATIVELY CONNECTED TO SAID CAPSTAN IN THE LOWERMOST 